The initial conditions for young massive cluster formation in the Galactic Centre: convergence of large-scale gas flows

Abstract

Young massive clusters (YMCs) are compact ($\lesssim$1 pc), high-mass (>10${}^4$ M${}_{\odot }$) stellar systems of significant scientific interest. Due to their rarity and rapid formation, we have very few examples of YMC progenitor gas clouds before star formation has begun. As a result, the initial conditions required for YMC formation are uncertain. We present high-resolution (0.13${}^{\prime \prime }$, $\sim$1000 au) ALMA observations and Mopra single-dish data, showing that Galactic Centre dust ridge `Cloud d' (G0.412$+$0.052, mass$\sim 7.6\times 10^4$ M${}_{\odot }$, radius$\sim 3.2$ pc) has the potential to become an Arches-like YMC (10${}^4$ M${}_{\odot }$, r$\sim$1 pc), but is not yet forming stars. This would mean it is the youngest known pre-star forming massive cluster and therefore could be an ideal laboratory for studying the initial conditions of YMC formation. We find 96 sources in the dust continuum, with masses $\lesssim$3 M${}_{\odot }$ and radii of $\sim$10${}^3$ au. The source masses and separations are more consistent with thermal rather than turbulent fragmentation. It is not possible to unambiguously determine the dynamical state of most of the sources, as the uncertainty on virial parameter estimates is large. We find evidence for large-scale ($\sim$1 pc) converging gas flows, which could cause the cloud to grow rapidly, gaining 10${}^4$ M${}_{\odot }$ within 10${}^5$ yr. The highest density gas is found at the convergent point of the large-scale flows. We expect this cloud to form many high-mass stars, but find no high-mass starless cores. If the sources represent the initial conditions for star formation, the resulting IMF will be bottom-heavy.

References in corpus (84)

• Young massive star clusters
• A geometric distance measurement to the Galactic Center black hole with 0.3% uncertainty
• On the Star Formation Rates in Molecular Clouds
• Re-examining Larson's Scaling Relationships in Galactic Molecular Clouds
• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Hi-GAL: the Herschel infrared Galactic Plane Survey
• Structural Analysis of Molecular Clouds: Dendrograms
• Global collapse of molecular clouds as a formation mechanism for the most massive stars
• Variations in the Galactic star formation rate and density thresholds for star formation
• Bias-free Measurement of Giant Molecular Cloud Properties
• Globular clusters as the relics of regular star formation in 'normal' high-redshift galaxies
• What controls star formation in the central 500 pc of the Galaxy?
• Fast and inefficient star formation due to short-lived molecular clouds and rapid feedback
• How Many Infrared Dark Clouds can form Massive Stars and Clusters?
• The dynamical evolution of molecular clouds near the Galactic Centre - I. Orbital structure and evolutionary timeline
• The E-MOSAICS Project: simulating the formation and co-evolution of galaxies and their star cluster populations
• Dense gas in the Galactic central molecular zone is warm and heated by turbulence
• Molecular gas kinematics within the central 250 pc of the Milky Way
• MALT90: The Millimetre Astronomy Legacy Team 90 GHz Survey
• Characterizing Precursors to Stellar Clusters with Herschel
• ATLASGAL --- Environments of 6.7\,GHz methanol masers
• Multi-temperature mapping of dust structures throughout the Galactic Plane using the PPMAP tool with Herschel Hi-GAL data
• The Millimeter Astronomy Legacy Team 90 GHz (MALT90) Pilot Survey
• The Bolocam Galactic Plane Survey IX: Data Release 2 and Outer Galaxy Extension
• G0.253+0.016: a molecular cloud progenitor of an Arches-like cluster
• Candidate super star cluster progenitor gas clouds possibly triggered by close passage to Sgr A*
• The linewidth-size relationship in the dense ISM of the Central Molecular Zone
• Gas flow in barred potentials
• A cluster in the making: ALMA reveals the initial conditions for high-mass cluster formation
• Turbulence sets the initial conditions for star formation in high-pressure environments
• 'The Brick' is not a brick: A comprehensive study of the structure and dynamics of the Central Molecular Zone cloud G0.253+0.016
• Distributed star formation throughout the Galactic Center cloud Sgr B2
• G11.92-0.61 MM 1: A fragmented Keplerian disk surrounding a proto-O star
• The Survey of Water and Ammonia in the Galactic Center (SWAG): Molecular Cloud Evolution in the Central Molecular Zone
• Mass inflow rate into the Central Molecular Zone: observational determination and evidence of episodic accretion
• The dynamical evolution of molecular clouds near the Galactic Centre - II. Spatial structure and kinematics of simulated clouds
• Molecular Line Emission from Massive Protostellar Disks: Predictions for ALMA and the EVLA
• Cloud-cloud collision as drivers of the chemical complexity in Galactic Centre molecular clouds
• There are no starless massive proto-clusters in the first quadrant of the Galaxy
• Galactocentric variation of the gas-to-dust ratio and its relation with metallicity
• Does External Pressure Explain Recent Results for Molecular Clouds?
• Detection of Widespread Hot Ammonia in the Galactic Center
• How to Find Young Massive Cluster Progenitors
• Seeding the Galactic Centre gas stream: gravitational instabilities set the initial conditions for the formation of protocluster clouds
• The W43-MM1 mini-starburst ridge, a test for star formation efficiency models
• Investigating the structure and fragmentation of a highly filamentary IRDC
• The dynamics and star-forming potential of the massive Galactic centre cloud G0.253+0.016
• Tracing the Conversion of Gas into Stars in Young Massive Cluster Progenitors
• On the temperature structure of the Galactic Centre cloud G0.253+0.016
• A multi-wavelength view of the Galactic center dust ridge reveals little star formation
• How do bound star clusters form?
• CMZoom: Survey Overview and First Data Release
• Abundant Methanol Masers but no New Evidence for Star Formation in GCM0.253+0.016
• The Formation and Early Evolution of Young Massive Clusters
• Characterization of the MALT90 Survey and the Mopra Telescope at 90 GHz
• Star Formation Rates of Massive Molecular Clouds in the Central Molecular Zone
• The Dense Gas Fraction in Galactic Center Clouds
• Star formation in a high-pressure environment: An SMA view of the Galactic centre dust ridge
• ALMA Observations of Massive Clouds in the Central Molecular Zone: Jeans Fragmentation and Cluster Formation
• The Physical and chemical structure of Sagittarius B2 -- IV. Converging filaments in the high-mass cluster forming region Sgr B2(N)
• A Census of Early Phase High-Mass Star Formation in the Central Molecular Zone
• Comparing Young Massive Clusters and their Progenitor Clouds in the Milky Way
• Characterizing the properties of cluster precursors in the MALT90 survey
• Fragmentation and disk formation in high-mass star formation: The ALMA view of G351.77-0.54 at 0.06" resolution
• Dynamically Driven Inflow onto the Galactic Center and its Effect upon Molecular Clouds
• H2O Southern Galactic Plane Survey (HOPS): Paper III - Properties of Dense Molecular Gas across the Inner Milky Way
• Young massive star cluster formation in the Galactic Centre is driven by global gravitational collapse of high-mass molecular clouds
• Cloud-cloud Collision in the Galactic Center 50 km s${}^{-1}$ Molecular Cloud
• Star formation in 'the Brick': ALMA reveals an active proto-cluster in the Galactic centre cloud G0.253+0.016
• A high cluster formation efficiency in the Sagittarius B2 complex
• The dynamical evolution of molecular clouds near the Galactic Centre -- III. Tidally--induced star formation in protocluster clouds
• ALMA Observations of Massive Clouds in the Central Molecular Zone: Ubiquitous Protostellar Outflows
• Temperature structures in Galactic Center clouds - Direct evidence for gas heating via turbulence
• On the physical mechanisms governing the cloud lifecycle in the Central Molecular Zone of the Milky Way
• ALMA view of G0.253+0.016: Can cloud-cloud collision form the cloud?
• Star formation in the massive "starless" infrared dark cloud G0.253$+$0.016
• CMZoom II: Catalog of Compact Submillimeter Dust Continuum Sources in the Milky Way's Central Molecular Zone
• Structure and kinematics of shocked gas in Sgr B2: further evidence of a cloud-cloud collision from SiO emission maps
• A Large--Scale Spectroscopic Survey of Methanol and OH Line Emission from the Galactic Center: Observations and Data
• A 6.7 GHz methanol maser survey of the central molecular zone
• A wind-blown bubble in the Central Molecular Zone cloud G0.253+0.016
• G337.342-0.119 (the "Pebble"): A Cold, Dense, High-Mass Molecular Cloud with Unusually Large Linewidths and a Candidate High-Mass Star Cluster Progenitor
• Cloud-Cloud Collision in the Galactic Center Arc

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